Insulating layers of different dielectric coefficient



H. MEURER April 21, 1931.

INSULATING LAYERS OF DIFFERENT DIELECTRIC COEFFICIENT Filed Oct. 9, 1925 f make Patented Apr. 21, .1931

UNITED STATS HANS manner, or'coroenn, camera, assrenoa rc rEL'rEn' & sumnmutm camswnnx ac'rmn-sasnmscmrr, or concern-mum, emmmn INSULATHTG LAYERS OF EDIIEFEBENT DIELEGIBIC 3 Application filed October 0, 1925, Serial No. 61,001, and in Germany Tannery 27, 1825.

This invention relates to insulating layers of different dielectric co-eflicient for the well known purpose of reducing the part voltages in the layers of higher dielectric co-efiicient 5 in non-homogeneous electric fields whereby an economy is effected in the total insulation if the succession ofthe layers takes place in the direction of decrease of the electric field intensity according to the decrease in the dielectric'co-eflicient. The im regnatedpaper insulation 'of high tension ca les and of their junction boxes and end joints constitutes a particularly important field of application of the invention. I I I have ascertained that the dielectric constant of paper insulation impregnated with an insulatingsub stance is the greater the more the specific weight of the aper that is used is increased by rolling un er pressure or by other pressure means. I

Accordin to the invention insulating layers of di ing paper are produced such a manner that the gradation of the dielectric constant is attained by a cone ondin gradation ofthe specific weight of the insu ating pa r produced by ro ling under pressure or y other pressure means.

The insulation of high tension cables, junction boxes and end iomt's is efi'ected according to the invention in such a manner that the" dielectric constant of the insulatin paper increased by increasing the speci 0 weight by rolling under pressure or by other pressure means, the more the-nearer the corresponding layer lies with respect tq the con-* ductor carrying the current. The accompanying drawing illustrates in crosssection one formof single core cable 40 constructed according to the invention The conductor a is surrounded by a plurality of insulating layers b, c, d; The specific weight of the paper employed in the layer 0 has been increased by rolling under pressure or by other pressure means as compared with the paper employed in the layer d and similarly the s cific weight of the paper em- Bloyed in t e layer 6 has been increased also v pressure with respect to the paper emnloved in the lever 0 rent dielectric-constant contain- What I claim is 2-- An electric cable having a graded insulation on the conductor consisting of a plurality of layers of similar paper, the paper forming said layers being compressed to various densities to produce correspondingly different dielectric constants, the dielectric con- "stan ts and the densities of the layers disposed nearest the conductor being the highest and gradually decreasing outwardly from the conductorn.

In testimony whereof I have signed my name to this specification.

, HANS MEURER. 

